Houston, TX 77005
3:00 p.m. Monday, Dec. 16, 2013
On Campus | Alumni
Sgr A* is a hundred times closer than any other supermassive black hole. It is surrounded by a highly unstable gas disk so why is the accretion disk so peaceful at the present time? This mystery has led to a flurry of models in order to explain why Sgr A* is radiating far below (1 part in 10^8) the Eddington accretion limit. But has this always been so? Evidence is gathering that Sgr A* has been far more active in the recent past, on timescales of thousands of years and longer. The bipolar wind discovered by MSX, the gamma-ray bubbles discovered by Fermi-LAT, the WMAP haze, the positronium flash confirmed by INTEGRAL, inter alia, are suggestive of something truly spectacular in the recent past. We present exciting new evidence that the Galactic Centre was a full-blown Seyfert just two million years ago. The echo of this incredible event can be seen today imprinted along the Magellanic Stream.
Speaker: Joss is a Federation Fellow and Professor of Physics at the University of Sydney, and Senior Fellow at Merton College, Oxford. He is a Fellow of the Australian Academy of Science and co-founder of the Institute of Photonics and Optical Science at Sydney (IPOS). Joss is a former member of the former Space Physics and Astronomy Department faculty at Rice University (1988-1993).
(This paper appeared in the November 1 issue of ApJ)
Cookies and tea afterwards!